JP3342660B2 - Communication method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to transmission systems and, more particularly, to access networks and high-speed data service delivery.

[0002]

2. Description of the Related Art A recent technology is a so-called available bit rate (ABR) asynchronous transfer mode (ATM) service category. There is a strong interest in utilizing ABR to transport ATM data traffic in broadband access networks using a suitable media access protocol.

[0003]

However, the problem with such technology is that with respect to interoperability, a general approach is required to handle the so-called ABR interaction with a media access control (MAC) unit or protocol. There is.

[0004]

SUMMARY OF THE INVENTION The problems and limitations of the prior art are that of a host digital terminal (HDT).
Terminal)) Uses a unique, simple and general ABR-MAC interoperable approach that minimizes the impact of the ABR connection of the ATM switch on the individual Information Appliance (IA) (IA at the customer premises) And by transferring the data to the ATM Network Interface Buffer (ATM-NI) at the HDT using the appropriate MAC protocol. For this purpose, using a unique configuration, A
Regulates the state of the buffer storage unit in the TM-NI.
Specifically, according to the present invention, the active IA-HD
It monitors upstream data traffic from the T connection and also monitors the initial IA-HDT connection. This means that two ATM-NI buffer storage unit thresholds selected according to the particular ATM-NI buffer storage unit capacity, a low (first) threshold and a high (second) threshold, are selected. It is realized by using. In an embodiment, the next upstream ATM in HDT
A predetermined parameter (k) is defined to specify the number of frames that must elapse before a cell is transmitted to the ATM-NI buffer storage unit. If the amount of data stored in the ATM-NI buffer storage unit is less than the low threshold, this means the normal "non-congested" operating state of the ATM-NI buffer storage unit. If the amount of data stored in the ATM-NI buffer storage unit is greater than the low threshold value but less than the high threshold value, the rate of data supplied to the ATM-NI buffer storage unit must be regulated. Must. If the amount of data stored in the ATM-NI buffer storage unit is greater than the high threshold,
No further data is allowed to be sent to the M-NI buffer storage unit.

A technical advantage of such an apparatus or method is that there is no need to pass parameters between the ABR and MAC protocol layers of ATM. Furthermore, it is not based on the specific MAC protocol used in the IA-HDT transmission link. In addition, it is operable on any broadband access network platform, such as a fiber coax hybrid configuration in loop access. Furthermore, it is computationally simple, requires relatively little memory, and can be implemented as an embedded function within a MAC protocol based on HDT.

[0006]

FIG. 1 is a simplified block diagram of a configuration using an embodiment of the present invention. As an example, subscriber home 101 has multiple information appliances (IAs) and corresponding transmission regulators. In this example, the IA includes a personal computer (PC) 102, an interactive television (ITV) unit 103, and an outdated unit 104.
And the corresponding regulators 105, 106 and 107
Is included. As will be apparent, other multimedia units can be used. In this example, the coaxial bus 108 is used to connect the IAs 102, 103 and 104 and the regulators 105, 106 and 107 to the fiber node 109, respectively. Further, the single-mode fiber 110 is used to connect the fiber node 109 to the host digital terminal (HDT) 111 and the media access control (MAC) unit 1 therein.
12 is connected. It should be noted that the protocol of the MAC unit 112 can be any that supports recovery and contention functions.
In this example, the MAC unit 112 is, for example, an adaptive digital access protocol (ADAP) that supplies received data to the ATM-NI buffer storage unit 113.
t (Adaptive Digital Access protocol)). A
For more information on the DAPt frame structure and the operation of the ADAPt MAC protocol, see "An Adaptive Digital
Access Protocol (ADAPt) For MultiserviceBroadband
Access Networks (Part 1 of 3): Protocol Descripti
on ", AT & T Contribution to IEEE 802.14 WG, Doc. # IE
EE 802.14-95 / 046, June 28, 1995, "An Adaptive Dig
ital Access Protocol (ADAPt) For Multiservice Broa
dband Access Networks (Part 2 of 3): Copy of Viewg
raphs ", AT & T Contribution to IEEE 802.14 WG, Doc. #
IEEE 802.14-95 / 046a-R1, June 28, 1995, and "An
Adaptive Digital Access Protocol (ADAPt) For Multi
service Broadband Access Networks (Part 3 of 3): P
erformance and Capacity Analysis ", AT & T Contributi
on to IEEE 802.14 WG, Doc. # IEEE 802.14-95 / 046b, J
l2_systemmessage [28, 1995]. The data is then provided to an ATM switch 115 over an ABR link 114 under the control of a unique ABR-MAC interoperable protocol according to the present invention. For more information about ATM ABR rate-based flow control and ABR service specifications, see "Traffic management specification Ver. 4.0", A
TM Forum Technical Committee, 1995, and "The r
ate-based flow control framework for the available
bit rate ATM service ", IEEE Network, March / April1
995, pages 25-39. Thus, in this example, the individual IA units 102-104 and HDT1
Transmission between the ATM unit 11 and the ATM-NI buffer storage unit 113 therein is performed in the MAC unit 112 layer. Cell rate regulation and admission control (admission) for active and so-called incipient IA-HDT connections using periodic explicit feedback from HST 111 to IAs 102-104 and corresponding regulators 105-107, respectively. Control) function. It should be noted that in this example, the feedback is periodic and saved. That is, coarse periodic feedback. Regulators 105-107 are implemented by using either the well-known ATM virtual scheduling or leaky bucket algorithm.
Further, each of the regulators 105 to 107 is an ATM-N
It has an external on / off control for temporarily stopping upstream transmission of ATM cells in the worst case congestion in the I-buffer storage unit 113. It should be noted that the connection of the ABR link 114 from the HDT 111 to the ATM switch 115 is in the ATM layer, and the minimum cell transmission rate (MCR)
rate) and peak cell transmission rate (PCR (peak ce
ll transmission rate)). These are negotiated when setting up the connection. Further, a feedback control approach as described in the IEEE Network article cited above is used to regulate the connection between the HDT 111 and the ABR link 114. The issue of interoperability is that ATMs in HDT111
-Appears in NI buffer storage unit 113. In order for the ABR link 114 bandwidth to fluctuate over time between peak and minimum cell rates, the IAs 102-104
A collection of ATM cells arriving at the HDT 111 from
This may cause an overload of the TM-NI buffer storage unit 113. By using the unique interoperable protocol of the present invention, when the ABR link 114 bandwidth is less than the aggregate cell rate of the ATM cells being supplied to the HDT 111, the fluctuation of the ABR link 114 bandwidth affects the IAs 102-104. And has no effect on the ATM-NI buffer storage unit 110.
Does not overflow. FIG. 1 and the above-described embodiment are, in particular, for example, digital subscriber lines (DSL).
(digital subscriber line) technology, copper loop, fiber in the loop (FITL)
p)) and other hybrid fiber coaxial (HFC (H
ybrid Fiber Coaxial) systems and subscriber loop multiplexing systems.

FIG. 2 is a flowchart illustrating the ABR-MAC interoperable protocol. The protocol starts at start step 201. Then, the conditional branch point 202
Is the ATM-NI buffer storage unit 113 (FIG. 1)
A test is performed to determine if the queue length in is less than the low threshold. If the test result is YES, step 203 corresponds to the j-th connection.
That IA-based regulators, MAC unit 112
The cell is transmitted at the initial rate k negotiated with (FIG. 1).
Note that in this example, k = 1 means that the IA-based regulator sends one ATM cell once for each upstream frame. A value of k greater than 1 means that less ATM is used because no cells are transmitted in each upstream frame.
Means that the cell will be transmitted. Thereafter, control returns to step 202 to determine whether the queue length is less than the low threshold. If the queue length is less than the low threshold, steps 202 and 203 are repeated until step 202 produces a NO test result and control passes to conditional branch point 204. Conditional branch point 204 performs a test to determine whether the queue length is greater than the official position. If the test result in step 204 is NO, this corresponds to the situation when the queue length in ATM-NI buffer storage unit 113 is between the low and high thresholds. In this case, the conditional branch point 205 performs a test for determining whether or not the connection is active. If the test result in step 205 is YES, the connection is active and control transfers to step 206. In step 206, an explicit forward congestion notification (EFCN)
ation)) Connections are selected in descending order of priority level, for which no parameters have been sent yet. Step 207
And the ATM cell in the next downstream frame is
It is transmitted to the selected connection together with EFCN (PTI = 1). The EFCN parameter is a payload type identifier (PTI (p
ayload type indicator)). PTI = 1 indicates that the EFCN has been received, and is interpreted as a notification that congestion exists in the ATM-NI buffer storage unit 113. PTI = -1
Indicates that the EFCN has not been received, and indicates that the ATM-
This is interpreted as a notification that there is no congestion in the NI buffer storage unit 113. At step 208, a parameter k is calculated for the selected connection.
In this example, the parameter k is calculated by the pseudo code shown in Table 1 below. In step 209, the IA regulator of the selected connection determines k based on the reception or non-reception of the EFCN in the subsequent frame.
Cells are transmitted once per frame. Thereafter, control returns to step 202. Returning to step 205, if the test result is NO, the connection is an initial connection and control proceeds to step 210. Step 210
Then, the reservation request is assigned to the initial connection based on the descending order of the connection priority level. Thereafter, control proceeds to step 202. Returning to step 204, if the test result is NO, the queue length in the ATM-NI buffer storage unit 113 is greater than the high threshold indicating worst case congestion. Step 211 performs a test to determine whether the connection is active. If the test result in step 211 is YES,
The connection is active and step 212
Select connections in descending order of priority. afterwards,
In step 213, the ATM cell is transmitted in the next downstream frame, and instructs the IA-based regulator corresponding to the selected connection to stop the upstream data transfer until receiving a notification of resumption of transmission in the future. . Thereafter, control returns to step 202. Returning to step 211, if the test result is NO, the connection is initial and control transfers to step 214. Step 214 selects connections in descending order of priority level. Then, step 215
Rejects the reservation request for the selected connection. Step 216 rejects the contention time slot indicating a collision , using well-known pseudo-collision techniques. Finally, step 217 broadcasts downstream ATM cells to all IA-based regulators indicating future reservation and contention time slot unavailability until a notification of future transmission resumption is received.
Thereafter, control returns to step 202. When control returns to step 202, the protocol proceeds as described above.

[Table 1] / * Pseudo code list Meaning of parameter k _j (t) = value of parameter k for connection j at time t v _j (t) = dummy variable d _j (t) = parameter k for connection j high threshold m the time delay Q between updates in the update before time t (t) = low threshold Q _H = the queue length Q _L = queue HDT-based ATM-NI queue _j = symmetric scaling factor P _j = priority of connection j u _j (t) ∈ {+1, -1} +1: EFCN received -1: EFCN not received Note: IA-based regulators One A for every kth upstream frame
Transmit the TM cell. * / Main () {for ( Q (t) <Q L) / * wait between queue size is a low threshold less than * / {return; / * control the IA-based regulator when the queue is not congested * /} For (Q _L ≤ Q (t) <Q _H ) / * While the queue length is between the low and high thresholds * / {v _j (t) = k _j ( td _j (t)) + m _j (P _j ) u _j (t); / * Equation 1 * / if (v _j (t) <0) {k _j (t) = 1;} else {k _j ( t) = v _j (t);}} for (Q (t) ≧ Q _H ) / * while the queue length is greater than or equal to the high threshold * / {k _j (t) = 0; / * queue length Stop cell transmission when is greater than or equal to high threshold * /}}

[0009]

As described above, according to the present invention, A
Without the need to pass parameters between the TM ABR protocol layer and the MAC protocol layer, the ATM AB
It is possible to provide interoperability between the R protocol layer and the MAC protocol layer.

[Brief description of the drawings]

FIG. 1 is a simplified block diagram of a configuration in which an embodiment of the present invention is used.

FIG. 2 is a flowchart illustrating an ABR-MAC interoperable protocol.

[Explanation of symbols]

 101 Subscriber's House 102 Personal Computer (PC) 103 Interactive Television (ITV) Unit 104 Legacy Unit 105 Regulator 106 Regulator 107 Regulator 108 Coaxial Bus 109 Fiber Node 110 Single Mode Fiber 111 Host Digital Terminal (HDT) 112 Media Access Control ( MAC) unit 113 ATM-NI buffer storage unit 114 ABR link 115 ATM switch

Continued on the front page (72) Inventor Vijay K. Bhagavath United States, 07738 New Jersey, Linkloft, Broadmoor Drive 45 (72) Inventor Curtis A. Schiller Jr. USA, 18810 Massachusetts, Andover, Winter Green Circle 3 (56) References JP-A-7-183886 (JP, A) 1996 IEICE Communications Conference, B-839 1997 IEICE General Conference, B -8-53 IEEE Comm. Mag. , Vol. 34 No. 3, p104-112 (58) Field surveyed (Int. Cl. ⁷ , DB name) H04L 12/56

Claims (24)

(57) [Claims] An asynchronous transfer mode (hereinafter referred to as "ATM") available bit rate (hereinafter referred to as "ABR") transport link (114) and a media access control (hereinafter referred to as "MAC") unit (11 ).
Communication method that provides interoperability with protocol 2)
The MAC unit (112) and a transmission regulator
The information device under the control of (105, 106, 107)
(102, 103, 104)
ABR assigned to a data connection for
To store data connected to the link (114)
Of using the storage unit with the queue (113), of (A) said information device (102, 103, 104) and the corresponding regulator (105, 106, 107)
Said storage assigned to a particular connection to one
Determining a data amount of at least one in the queue unit (113), a step (202) for comparing at least a first threshold value (B) the determined amount of data, it is determined (C) If the data amount is smaller than the first threshold value, the regulator (105, 106, 107) is a predetermined initial transmission rate of the ATM cells from said information device corresponding to the information device (102, 103, 104)
And controlling so as to adjust the transmission in order to determine the amount of data in the (D) If the determined amount of data is not smaller than the first threshold value, the assigned storage unit queues, a step (204) for comparing the determined amount of data and the second threshold value, (E) the determined data amount is the second in the first threshold value or more
Generating a control parameter if not greater than the threshold value (205-208) ; and (F) controlling a regulator corresponding to the information device to adjust an ATM cell transmission rate from the information device. Transmitting the control parameters to a regulator corresponding to the information device (207-2).
And 09), a regulator corresponding to (G) if the determined data amount is larger than the second threshold value, the information device, the information
(H) controlling the transmission of the ATM cell from the broadcast equipment to be prohibited (211 to 217) ; (H) determining whether the connection to the information equipment is active (205, 211) ; and (I). If the connection is active, the information
Select connections to devices according to descending priority
It from the step (206 and 212), the control parameter is generated (208) in accordance with predetermined criteria based on the delay interval between the last update and the current update in the transmission rate from the information device, the Said unit queue of the MAC unit (112)
Control the transmission rate from information equipment according to the congestion level of
By controlling the MAC unit (112)
A communication method, wherein interoperability of the ABR link (114) is achieved . 2. The method according to claim 1, wherein the determined data is the first threshold.
Greater than the threshold value and less than the second threshold value
And when the connection is not active (20
5), the reservation request is made based on the descending order of the connection priority.
Further comprising the step of making an assignment (210).
The communication method according to claim 1, wherein 3. The method according to claim 1, wherein the determined data is the first threshold.
Greater than the threshold value and less than the second threshold value
When the connection is active, the connection
The action is an explicit forward congestion notification (hereinafter referred to as EFCN).
Say. ) Parameters are selected as not transmitted
(206) is further provided.
The communication method according to claim 1. Wherein said predetermined criteria, prior to said information device
Further, based on the priority of the serial connection (206), The method according to claim 3, further comprising a step (206 to 208) for transmitting said control parameters to said information device on the selected connection. 5. The information device on a selected connection
Vessel in response to the control parameter, according to whether EFCN parameters have been received by said information device on which the selected connection at the previous frame based on the adjusted ATM transmission rate, the ATM cells in the ATM frame Controlled to send
The method of claim 4 , wherein (209) . Wherein the control parameter, wherein the before the next ATM cell is transmitted from the information device <br/>, specifies the number of frames elapsed (208) that. 7. The step (E) of generating the control parameter includes: k = v _j (t) = k _j (t−d _j (t)) +
generate the control parameters according to m _j (P _j ) u _j (t), where k is a control parameter and k
_j (t) is the value of control parameter k for connection j at time t, v _j (t) is a dummy variable, and _dj (t) is the most recent previous update of connection parameter k for connection j and The time delay between updates of the control parameter k at time t, m _j is the symmetric scaling factor, p _j is the priority of connection j, u _j (t) ∈ ｛+1,
-1}, and the +1 is an explicit forwarding congestion notification (EF
2. The method of claim 1 , wherein CN) indicates that connection EF has been received, and -1 indicates that EFCN has not been received for connection j. 8. When the value of v _j (t) is less than 1,
The method of claim 7, comprising the step of setting k = 1. 9. The method according to claim 8, wherein the determined data is the second threshold value.
The connection to the information device is larger
If not active (211), connect to the information device
Options according to descending priority (214),
Step of refusing a reservation request for the selected connection
The method according to claim 1, wherein (215) is provided.
Law. 10. For all information equipment regulators,
Until future notification of resumption of ATM cell transmission is received, non-use of future reservations and contention time slots
The method of claim 9, wherein the this <br/> comprising the step (217) for broadcast transmission sexual instruction. 11. When the connection to the information equipment is not active (211), according to claim 10, characterized in that it comprises a step (216) to turn down the contention time slots to the selected connection
The described method. 12. The method according to claim 11, wherein the contention time slot includes a step of rejecting using a pseudo-collision technique.
The method of claim 11, wherein a has. 13. An asynchronous transfer mode (hereinafter referred to as "ATM").
Say. ) Available bit rate (hereinafter “ABR”)
U. ) Transport link (114) and media
Access control (hereinafter referred to as “MAC”) unit (11).
2) a communication device providing interoperability between: (X) the MAC unit (112);
Information under the control of the radiator (105, 106, 107)
Transfer data from devices (102, 103, 104)
Assigned to the data connection for the AB
For storing data associated with the R link (114).
A storage unit (113) provided with a queue for the information equipment ; (A) the information devices (102, 103, 104) and
And corresponding regulators (105, 106, 107)
The amount of data in at least one allocated queue
And means (111) determines, (B) determining the amount of data at least a first threshold value
(111; Step 20)
And (G) the determined data amount is larger than the second threshold value.
In case of transmission, the transmission of ATM cells from the information equipment is prohibited.
Means for generating an instruction to be transmitted to the information device
And (F) an ATM cell transmission rate for the information device.
The control parameters provided to the information device for controlling
Means for generating data (111; steps 202, 20)
And 3 or via 202,204-208), (C) small determined data amount than the first threshold value
In response to the request, the control
Means for setting parameters (111;
(EI) , and (EI) when the determined data amount is equal to or more than the first threshold value and
2 In response to the threshold being less than
The last update and the current update at their transmission rate
Said control according to a predetermined criterion based on the delay interval between
Means for generating parameter values (111; step 20)
And 2,204-208 via), in active connection to (H) the information appliance
Means (111; step 205 or
(I via 211); and (I) if the connection is active, the information
Connection to the broadcast equipment in descending order of priority
Means (111; via step 206 or 212)
If, from now, the unit queue of the MAC unit (112)
Transmission rate from the information device according to the congestion level of
Controlling the MAC unit (112)
And the ABR link (114) interoperability is achieved.
A communication device, comprising: 14. The data according to claim 1, wherein said determined data is said first data.
Greater than the threshold and less than the second threshold
In response, when the connection is not active (2
05), means for allocating a reservation request (111; step
202, 204, and 210).
The communication device according to claim 13. 15. The method according to claim 15, wherein said determined data is said first data.
Greater than a threshold value and less than the second threshold value
When said connection is active in response to
The connection uses an explicit forward congestion notification (hereinafter referred to as E
It is called FCN. ) Parameter is not transmitted
Means (111; steps 202, 204,
205, 206).
14. The communication device according to claim 13. 16. The information processing apparatus according to claim 16, wherein the predetermined criterion is
Based on the priority of the connection, the selected
The control parameters to the information device on the connection
Characterized by further comprising means (111) for transmitting
The communication device according to claim 15, wherein 17. The information device, wherein the control parameter is
According to the adjusted ATM transmission rate.
In the previous frame on the selected connection
Whether the EFCN parameter was received by the information device
Depending on whether the ATM cell in the ATM frame
Including transmission means (via step 209)
The communication device according to claim 16, wherein 18. The information processing device according to claim 18, wherein the control parameter is
That elapses before the next ATM cell is transmitted from the transmitter
The number of programs is specified (via step 208).
Communication device. (19)Means for generating the control parameter
(111; via step 208), k = v _j (T) =
k _j (T−d _j (T)) + m _j (P _j ) U _j According to (t)
Generate the control parameters, where k is the control parameter.
And k _j (T) is the connection at time t
Is the value of the control parameter k for
_j (T) is a dummy variable, d _j (T) is connection
most recent before connection parameter k for j
And the control parameter k at time t
Is the time delay between _j Is a symmetric scaling
And p _j Is the priority of connection j,
u _j (T) {+1, -1}, where +1 is specified
Forwarding congestion notification (EFCN) for connection j
-1 indicates that the EFCN is connected.
Feature that it has not been received for
The communication device according to claim 13, wherein: 20. A means for generating the control parameter
Sets k = 1 if the value of v _j (t) is less than 1.
20. The communication device according to claim 19, wherein: 21. A method according to claim 21, wherein said determined data is said second data.
The threshold is greater than the threshold and the connection to the information
Response to the information device is not active.
When actions are selected according to descending priority,
Means for rejecting a reservation request for the selected connection (11
1: Steps 202, 204, 211 , 214 , 215
14. The communication according to claim 13, comprising:
apparatus. 22. The method according to claim 19, wherein the determined data is the second data.
The threshold is greater than the threshold and the connection to the information
Response to the information device is not active.
When actions are selected according to descending priority, all
Recovery of ATM cell transmission for information equipment regulator
Reservations and content until you receive
Broadcast time slot unavailability indication
Means (111; steps 202, 204, 211, 21)
22, via 217).
The communication device as described. 23. The connection to the information device is
In response to being inactive, the selected
Hands refusing contention time slot to Nection
Characterized by having a step (111; via step 216)
23. The communication device according to claim 22, wherein: 24. The contention time slot
Means to be refused using quasi-collision technology (111;
24. The method according to claim 23, wherein
Communication device.